Method of treating hydrocarbons



tion products formed during the process.

Patented July 3, 193

IHETHQD OF TREATENG HYDROCAREONS Gerald G. Connolly, Baltimore, Md, assignor, by

mesne assignments, to Qhester F. Hoclzley, receiver for The Silica Gel Corporation, Baltimore, Md, a corporation of Maryland No Drawing.

Application August 29, 1930,

Serial No. 478,789

2 @laims.

The present invention relates to a method of stabilizing refined hydrocarbon distillates, and more particularly, to those distillates distilled from refined products containing practically all 5 of the reaction products formed during the refining treatment.

In certain processes of refining liquid hydrocarbons, the last step has been a distillation in order to separate 1e refined oil from the reac- Frequently, products refined by these processes are not stable with respect to color and gum formation when stored.

It is the principal aim of the present invention to render these refined products stable with re spect to color and gum formation.

To this end the distillate mentioned above is treated with an aqueous liquid and then the distillate separated therefrom. This removes traces of impurities such as acid that might react with invention, consists in treating the unrefined liquid hydrocarbon containing gum forming constituents with a small amount of a substance capable of reacting with said constituents to polymerize a portion of them. This causes a small amount of sludge, which is separated from the oil. Then the hydrocarbon is treated at an elevated temperature (250 to 300 F.) and at a pressure sufficient to keep it in the liquid phase, with a solid porous adsorbent material such as silica gel.

' 40 After the treatment with the adsorbent, practically all of the reaction products formed during the refining treatment are present and in order to separate the refined oil from these reaction products, the oil is distilled. Usually sulphuric as acid of about 80% to 93.5% strength is employed in the first step of the process to react with a portion of the gum forming constituents. Usually about 0.2% to 1% of the acid by weight of the hydrocarbon is used. This process is described 59 in application Serial Number 276,163, filed May Another method of refining these oils which precedes the treatment according to the present invention comprises treating the unrefined oil 155 with a large amount of sulphuric acid of a (Cl. Hid-146) strength corresponding to 62 to 64 B., the amount of acid used being about 4% by weight of the oil treated, agitating the mixture thoroughly, then adding water in an amount equal to twice that of the acid used, separating the acid from the mixture, neutralizing the treated oil, and then distilling. The water throws the reaction products back into solution so that prior to distillation, the oil contains practically all the reaction products. This process is described more in detail in British Patent 251,117.

The washing step of the present invention is particularly necessary when the hydrocarbons have been refined by either of the processes mentioned above or similar processes. It is not really necessary when the oil has been treated by the old acid process, employing a large amount of strong acid, since most of the products of reaction are removed with the sludge.

Although the refined products obtained by the two processes mentioned above are entirely satisfactory as motor fuels, they will not withstand long periods of storage without falling off in color and the formation of some gums. This is probably initiated by refining chemicals left in the oil and/ or reaction products formed during the refining treatment.

It has been found that treating the refined distillate distilled from a treated product containing virtually all or" the reaction products with an aqueous liquid renders the distillate color and gum stable. The aqueous liquid employed may be either water or an aqueous solution of an alkali such as sodium hydroxide, sodium carbonate, or calcium hydroxide. if the aqueous solution containing alkali is employed, it should contain only a very small amount of alkali, say not inore than 0.1 of one per cent. The presence of any alkali in the final product is extremely harmful because it reacts with unsaturated hydrocarbons, 95 forming products which seriously impair the stability of the refined product.

The refined distillate and aqueous liquid such as water, are thoroughly mixed. This may be accomplished by causing the distillate and water to flow through a knot-hole mixer. After this thorough mixing, the distillate is separated from the water in any wel1-known manner as by means of a separator.

The product obtained by the process of the present invention may be stored for long periods of time without going off in color or forming gums.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

containing gum forming constituents which consists in treating the hydrocarbon with a small quantity of a substance capable of reacting with the gum forming constituents to polymerize a portion of the same, treating the hydrocarbon with a solid porous adsorbent material at an elevated temperature and pressure sufficient to keep the hydrocarbon liquid, and distilling, the step of then Washing the distillate with an aqueous liquid, and separating the liquid and hydrocarbon.

GERALD C. CONNOLLY. 

